Guidance Protocol: Application of Nucleic Acid-Based Tools for Monitoring Monitored Natural Attenuation (MNA), Biostimulation, and Bioaugmentation at Chlorinated Solvent Sites

Reductive dechlorination is a promising process for biodegradation of chlorinated solvents. The successful field evaluation and implementation of the reductive dechlorination process is dependent on a comprehensive understanding of contaminant, geochemical, and microbial data. Nucleic acid-based tools are commercially available to identify relevant Dehalococcoides (Dhc) bacteria. These tools detect and quantify Dhc 16S rRNA genes and three Dhc reductive dehalogenase (RDase) genes involved in the reductive dechlorination of chlorinated ethenes. These tools were demonstrated and validated in ESTCP Project ER-0518 (Application of Nucleic Acid-Based Tools for Monitoring Monitored Natural Attenuation (MNA), Biostimulation, and Bioaugmentation at Chlorinated Solvent Sites). The application of nucleic acid-based molecular biological tools (MBTs) can result in significant cost reductions and reduced project time-lines. There are several sampling methodologies available to field practitioners. The selection of groundwater sampling methods can significantly influence the quantification of Dhc biomarker genes. The sampling and handling procedures described herein have been validated for Dhc assessment at chlorinated solvent sites. These techniques can also be applied to sites impacted with other contaminants. By clearly understanding how site geochemistry and Dhc abundance affect contaminant transformation and detoxification, MNA, biostimulation, and bioaugmentation, remedies can be designed and modified to optimize the efficiency of bioremediation treatments. Environmental Restoration Project. Prepared in collaboration with Geosyntec Consultants, the University of Tennessee, and Tetra Tech, Inc. The original document contains color images.